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Sat Mar 13 19:08:53 UTC 2010
On Sat, 13 Mar 2010 18:03:42 +0000
Matthew Seaman <m.seaman at infracaninophile.co.uk> wrote:
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> On 13/03/2010 14:47:31, Антон Клесс wrote:
> > I saw that more than year ago on my teacher's server, when I was
> > deal with my first FreeBSD, so it's just a kind of habit.
> It's a bad habit you should try and cure yourself of. Stepping the
> clock with ntpdate(8) can cause nasty effects like time apparently
> going backwards -- and that will seriously upset a lot of software.
> Also, it doesn't account for the natural clock drift of your system,
> so it's going to give you pretty terrible accuracy -- probably good
> to no more than a few seconds. ntpdate(8) is really only intended to
> get the clock into the right ballpark at system boot so that ntpd(8)
> has a fighting chance of getting into synch. The NTP project has
> deprecated ntpdate(8) for some time now, and instead prefers adding
> an option to ntpd(8) to say "set the clock on initial startup no
> matter how far out it is."
> > But on the other hand, if it exists, it could work properly, and I
> > am interested in just to understand, how it should be set up.
> I'm assuming you're on some sort of always-on network, like ADSL?
> Most people are nowadays. In which case, there's really no reason
> not to run ntpd(8) the way it is intended to be used.
> Just add the following to /etc/rc.conf:
is not a complete substitute for running ntpdate at startup. It allows
ntpd to make a large correction, but it doesn't block the boot sequence
so you could still get a large step-change later-on when your daemons
ntpd has an option to emulate ntpdate, but it holds-up the
boot-sequence much longer - presumably this is why ntpdate has been
deprecated for a long time but hasn't yet gone away.
you can run ntpdate at boot with
the rc script gets the servers from ntp.conf
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